The purpose of this experiment was to determine whether the color of
carbonated water affected perception of its taste.

I became interested in this idea because I wanted to do something like
a taste test. At first I was thinking about testing soft drinks.
Then I saw a project done by Krista Garcia in 2003 as a 7th grader. I
knew it was exactly the kind of experiment I wanted to do. I decided to
make some changes to her idea that might make it better. My
project is called “Drink color vs. Taste perception.”

The information gained from this experiment will be useful to caterers,
cooks, or anyone who is involved in food or drink preparation.

HYPOTHESIS

My first hypothesis was that color would affect the perceived taste of
the flavored water.

I based my first hypothesis on previous research done by Krista Garcia.
She stated,”...the color of the flavored carbonated water affected the
reported taste.” Her research can be found at
http://www.selah.k12.wa.us/SOAR/SciProj2003/KristaG.html

My second hypothesis was that the red food coloring would be most
effective in misleading the perceived taste.

My third hypothesis was that lemon-lime flavored water would be most
unaffected by misleading colors.

Experimental Design

The constants in this study were:

The amount of carbonated water tasted (20ml)

Brand of flavored, sugar free carbonated water

Size, color, and type of tasting cup

Grade of subject

Temperature of carbonated water (7°C)

Location experiment took place

Experimenter interacting with subjects

Type and amount of food coloring

Procedures used

The manipulated variable was the color of the carbonated water.

The responding variable was the percentage of times subjects accurately
identified the taste.

To measure the responding variable I will count the number of correct
responses.

MATERIALS

QUANTITY

ITEM DESCRIPTION

1

Box of gloves (latex free)

4
liters

Unsweetened Carbonated
Water, Lemon Lime flavored

4
liters

Unsweetened Carbonated
Water, Strawberry Flavored

4
liters

Unsweetened Carbonated
Water, Tangerine Flavored

500

DIXIE cups

1

Refrigerator that has a
temperature of 7°C

1

Garbage can

30

Response Sheets

1

Box of Pens or Pencils

1

Pack of food coloring
(Green, Orange, & Red)

1

One Liter Liquid Measuring
Cup (that can measure 20ml)

PROCEDURES

1. Collect permissions slips before experiment is conducted (subjects
may not participate without the slips.)
2. Create response sheet for subjects to use during tastings.
3. Prepare carbonated water:
a. Buy 4 liters of each flavor of sugar-free carbonated water at the
grocery store (strawberry, tangerine, & lemon-lime) also buy 500
small drinking cups to serve carbonated water and food coloring with
the colors of green, red, and orange or yellow.
b. Select one flavor of water to color. Into a one-liter bottle of this
flavor add five drops of red food coloring.
c. Shake bottle gently for 12 seconds to spread the color.
d. Refrigerate bottle at 7°C
e. Repeat steps b-d with another bottle of this same flavor but add the
next food color in this list (green, red, or orange.)
f. Repeat step e until all 3 bottles of this flavor are different
colors.
g. Repeat steps b-f with three bottles of the next flavor.
h. Repeat step g with each of the last flavor.
4. Move 6 desks in testing classroom so that none of the subjects can
communicate or see each other’s paper.
5. Wash desktops.
6. Bring a group of 6 students into testing room and seat them
7. Read subjects the instructions and answer any questions. Tell
them they may quit at any time.
8. Give each subject a response sheet and a pencil.
9. Pourer and server must wash hands before serving liquids or touching
cups and put gloves on.
10. Conduct trial using the Sampling Order table.
a. The pourer, who is hidden from the subjects, puts 20 ml. of the
correct color and flavor carbonated water for this trial into 6 of the
small sample cups.
b. Server (only) gives subjects the carbonated water.
c. Tell subjects to taste it then mark on the response sheet the flavor
they think the water is. Make sure the response is marked for
this trial and color.
d. Repeat steps 10 a-d until all four colors of water have been tasted
for this trial.
11. Conduct the remaining three trials repeating step 10.
12. Thank the subjects and send them back to class
13. Collect response sheets and discard used cups.
14. Wash desktops. Wash hands.
15. Repeat steps 6-14 for the rest of the groups that you test.
16. Tally correct responses using Sampling Order sheet as a guide.
17. Average scores

RESULTS

The original purpose of this experiment was to determine whether the
color of carbonated water affected perception of its taste.

The results of the experiment were that strawberry flavored water was
correctly identified most (2.0 of 3.0 possible), and lemon-lime was the
least often identified (1.6 of 3.0 possible). The waters colored
red were identified correctly least often (1.7 of 3.0 possible) and
orange colored water was identified correctly most (1.9 of 3.0).

My first hypothesis was that color would affect the perceived taste of
the flavored water.

The results indicate that my first hypothesis should be accepted, but
the difference is extremely small.

My second hypothesis was that the red food coloring would be most
effective in misleading the perceived taste.

The results indicate that my second hypothesis should be accepted,
because red colored water had the fewest correct taste identifications
(so it was most misleading.)

My third hypothesis was that lemon-lime flavored water would be most
unaffected by misleading colors.

The results indicate that my third hypothesis should be rejected
because the strawberry flavor was identified correctly the most
frequently.

Because of the results of this experiment I wonder how accurately
people could identify the flavors with no coloring at all. It is
possible that these flavors are not easy to identify no matter
what. I am also interested in doing this test using adults
compared to kindergarteners. Really young kids might be more
affected by the colors.

If I were to conduct this project again I would use all unsweetened
carbonated water. I would include many more subjects in my study.

RESEARCH REPORT

Introduction
It is likely that people learn and become familiar with specific
combinations of colors and tastes. The color/taste combinations
become part of a person's memory, and people begin to expect certain
colors to be associated with certain tastes.

Taste
Taste is an important sense by which human beings and animals detect
many chemicals in the environment. In the body, specialized skin cells
that detect tastes are grouped into clusters called taste buds. They
are found primarily on the tongue, contained within small mounds called
papillae. Taste buds also are present on the palate (back of the tongue
on roof of the mouth) and other parts of the throat and mouth. The word
taste refers to the quality of substance that is detected by taste
buds. Taste is a component of flavor, smell, touch, and temperature
sensation.

There are five primary taste sensations: salty, sour, sweet,
bitter, and umami. The taste of "salt" comes from sodium ions.
Sour taste is caused by acids. Sweet taste (like from sucrose, or
sugar,)is kind of the same as our odor receptor cells. Humans have at
least 24 genes that "encode" bitter receptors. Umami receptors respond
to the salts of glutamic acid like monosodium glutamate- a flavor
enhancer used in many processed and especially Chinese
foods. It is associated with amino acids or the building
blocks of protein. Bacon hits our umami receptors because it is a
rich source of amino acids.

A single taste bud contains 50-100 taste cells representing all five
taste sensations. It used to be believed that there were separate taste
areas on the tongue. That has been proven to be untrue.

“Taste is important to our health for the following reasons.
Sweet foods are generally not poisonous, and provide needed calories.
Sour fruits generally have needed vitamin C. We need a certain amount
of sodium to remain healthy. “Umami is a signal for the presence of
protein, which we need to survive. Finally poisonous substances, such
as many alkaloids, are generally bitter” (D.R. Bauer et al, Cornell
University).

Taste is also influenced by smell. Holding your nose while eating
something will probably make it difficult to identify the taste.

Color
Many people don't realize how important color is to taste
perception. Color affects our psychological impression of food. "If you
don't believe it, try eating a familiar food in the dark."

The colors used in foods and beverages came from both natural and
synthetic sources. Think about orange juice and the natural color of
the orange. Think about yellow lemons. People become
familiar with specific combinations of colors and tastes. People
start to expect certain tastes to be associated with specific colors.

Food and drink companies are very interested in whether color
affects taste perceptions. Companies work very hard to make
their drinks the most desirable so they can sell more. If the company
determines that changing the color of a drink can sell more product,
you will probably see them change the color.

In a study by DuBose et al., it was reported that subjects
identified the correct flavor more often when the drink had the
expected color. For example, an orange-colored drink that was
actually cherry flavored was often thought to taste like an orange
drink; a green colored cherry drink was identified by many as lime.

In another study by Oram, N., it was reported that younger
subjects relied more on the color of the drink than adults did.
In other words, the younger subjects made more color-associated errors
in identifying the correct flavor.

Flavor
Combining the sensations brought about by food or drink results in
"flavor". Smell, taste, feel in the mouth, and sight all impact
the flavor of food and drink. Chefs at fancy restaurants are
aware of this, and try to create a "flavor", not only with the food and
drink, but also with atmosphere. This is all done to alter
people's perceptions of their product. An environment that is
comfortable, has attractive smells; and a product that is presented in
a beautiful "package" is probably going to be more desirable.

Tongue
Tongue is the chief organ of taste. It also helps in chewing and
swallowing, and helps to make words come out of your mouth right. The
tongue is a muscle in the mouth.

Taste Buds
The average human has about 10,000 taste buds; however, they're not all
on the tongue. Some are under the tongue; some are on the inside of the
cheeks; some are on the roof of the mouth. Some can even be found on
the lips; these are especially sensitive to salt. Skin on top
surface contains 10,000 tiny chemical sensing bodies called taste buds.
The tongues spongy looking surface accur in four shapes: filiform
(pointed), foliate (leaf shaped), fungiform (mushroom shaped), and
circumvalete (ring shaped). Each poliate, fungiform, and circumvalete
papilla holds 1-200 taste buds. Filiform papillae are the most numerous
type. They contain no taste buds. Inside of a taste bud are a dozen
taste cells, and there can be up to 10,000 taste cells on a tongue.